Twelve-Year Trajectory of Disease Burden and Mortality by Obesity Level in Korea: Analysis of the National Health Insurance Service Database

Introduction Despite increases in obesity prevalence, awareness of obesity as a disease requiring active treatment remains lacking in Korea. We investigated differences in medical problems and expenditures and mortality across obesity categories using 12-year data from the National Health Insurance Service. Materials and Methods Individuals aged 40-79 years who underwent medical examinations during 2003-2004 (n = 415,201) were divided based on Asian body mass index (kg/m(2)) criteria: normal weight (18.5 to <23.0, 36.4%), overweight (23.0 to < 25.0, 28.3%), obesity (25.0 to < 30.0, 32.5%), and severe obesity (>= 30.0, 2.8%). Medical problems and expenditures were fitted to linear mixed models. Mortality was analyzed via Cox proportional-hazards model. Results More severe obesity was associated with a higher rate of medical problems, relative to normal weight: coefficient =0.31 (95% confidence interval [CI], 0.30-0.32) for overweight, 0.61 (0.60-0.61) for obesity, and 1.07 (1.04-1.09) for severe obesity. A similar association was observed for medical expenditure: coefficient =8.85 (95%CI, 6.80-10.89) for overweight, 20.04 (18.07-22.01) for obesity, and 48.76 (43.66-53.86) for severe obesity. Relative to overweight participants, those with normal weight and severe obesity exhibited a higher mortality risk (hazard ratio [HR] 1.21 [95%CI, 1.18-1.25] for normal; 1.27 [1.19-1.36] for severe obesity). In agespecific analyses, mortality risk was the highest for participants with severe obesity, aged< 60 years (HR, 1.58 [95%CI, 1.41-1.77]). Conclusion Disease burden including medical problems and expenditure, and mortality in middle-aged adults, increased proportionally to the degrees of obesity. Health policies and medical systems aimed at reducing the burden of obesity may help reduce the burden of disease on society.